Posted
by
Soulskillon Saturday March 17, 2012 @05:00PM
from the i-can-see-my-house-from-here dept.

An anonymous reader writes "On Thursday Felix Baumgartner climbed into a capsule carried by a balloon, floated up to 71,500 feet, and jumped out. He free-fell through the atmosphere for almost four minutes, hitting an estimated top speed of 364 mph. 'I wanted to open the parachute after descending for a while but I noticed that I was still at an altitude of 50,000ft,' he said. After finally deploying his chute, he fell for a bit over four more minutes, before successfully touching down in the New Mexico Desert. This was a test to prepare him for a jump of 120,000 feet later this summer, during which Baumgartner will break the record for highest free-fall jump — and the sound barrier. '... a 36-pound spacesuit is all that separates Baumgartner from a hostile world that would boil the blood in his body. Baumgartner will wear a chest pack crammed with data-hungry instruments to help ground controllers monitor the attempt — and log scientific data. Some will keep tabs on his heart rate and oxygen intake to see how a body in a spacesuit reacts to a boundary no one has broken (and lived to tell the tale): the speed of sound.'"

He free-fell through the atmosphere for almost four minutes, hitting an estimated top speed of 364 mph. 'I wanted to open the parachute after descending for a while but I noticed that I was still at an altitude of 50,000ft,' he said.

Jo Kittenger reported much the same thing, that high up there is no sense of movement, even though you are travelling extremely fast, and the ground does not appear to be getting closer because it is so far away and there is no sense of scale...

Survival is not required for being the first person to break the sound barrier without a means of propulsion.

He is not that first: astronauts do it all the time because a space craft does not use it engines once it is in orbit. If your argument is that they use propulsion initially to get to orbit then the same can be said of this attempt because it uses a mean of propulsion to get him up to ~40km high. Besides from a physics point of view, since the earth orbits the sun at ~29km/s, every human is already travelling at well over the speed of sound without propulsion and has been doing so since we first evolved -

And as far as surviving such a jump, I think he wants to be in good health afterwards - since theres a good chance that he could be alive, but paralzed due to the injuries suffered.which would not be much fun.

Of course if he doesn't make it he is guarranteed the Darwin award anyway

I'm sure they're withholding it until he does the final big jump for maximum effect. It'll probably be in the documentary, as well. If you go to their website they have quite a bit of footage that they've released so far.

The dangerous part is if you start to spin, there isn't much you can do to stop it from happening.... drogue or not. This is because of the extreme altitude as there isn't much air to interact with at all.

Kittinger's first Excelsior test at "merely" 76,000 feet nearly cost him his life when he went into a flat spin eventually rotating at 120 rpm before he finally got it under control after passing out due to the fact that his main chute automatically deployed and broke the spin. This problem also happens to high altitude aircraft, but they usually have some kind of rudimentary control surface to work with and some high altitude aircraft even have "thrusters" to help with aircraft orientation if it becomes a problem... at least being able to partially control the jet exhaust in some manner.

When you get to a lower altitude, the drogue chute is much more useful and can be used.... but you need to get to that altitude where it can be useful in the first place. This is called extreme skydiving for a good reason.

Bailing out at supersonic speed and surviving is possible. Per Wikipedia:

"In the early 1960s, deployment of rocket-powered ejection seats designed for use at supersonic speeds began in such planes as the Convair F-106 Delta Dart. Six pilots have ejected at speeds exceeding 700 knots (1,300 km/h; 810 mph). The highest altitude at which a Martin-Baker seat was deployed was 57,000 ft (from a Canberra bomber in 1958). Following an accident on 30 July 1966 in the attempted launch of a D-21 drone, two Lockheed M

Except that he won't be going that fast by the time he pulls his parachute. Once he's closer to the ground, the air will be a lot thicker, and his terminal velocity a lot lower. Once it's time to pull the chute, he'll likely be falling at the same rate as your average skydiver. Plus, like Kittinger, I'm assuming there will be a drogue chute deployed much earlier to keep him stable.

Kittinger did several flights of this sort. Manhigh I and Excelsior I, II, III. There may have been others. I'm not that well versed on old USAF projects.

As I recall from interviews I've read regarding the 1st flight, Kittinger was flying blind for a good bit of the ascent. His visor frosted over, so he couldn't see anything, including his altimeter. On the 3rd flight, his right glove leaked, causing his hand to swell. There was no permanent injury from that though.

While not mentioned in the summary, it's in the story that Kittinger is consulting on Baumgartner's jumps. He's also been planning it for a while. Here's a 2010 story on it.

As far as I know, there were no failed attempts of this sort. Well, not that resulted in the person not surviving, despite the blurb at the end of the summary. Well, it fails twice in that Kettinger did break the speed of sound.

I don't understand the references to hand-swelling and blood-boiling? At most the difference in pressure throughout the fall will be 1 atmosphere. In scuba diving that really isn't much at all (33 feet down). The world record for freediving (no tanks, i.e. quick up and down) is almost 900 feet.

theory predicts -- and animal experiments confirm -- that otherwise, exposure to vacuum causes no immediate injury. You do not explode. Your blood does not boil. You do not freeze. You do not instantly lose consciousness.
Various minor problems (sunburn, possibly "the bends", certainly some [mild, reversible, painless] swelling of skin and underlying tissue) start after ten seconds or so. At some point you lose consciousness from lack of oxygen. Injuries accumulate. After perhaps one or two minutes, you're dying. The limits are not really known.

You do not explode and your blood does not boil because of the containing effect of your skin and circulatory system. You do not instantly freeze because, although the space environment is typically very cold, heat does not transfer away from a body quickly. Loss of consciousness occurs only after the body has depleted the supply of oxygen in the blood.

I wonder, can you hold your breath in space? Or does your chest feel like it's getting crushed until you let the breath out? Or would it feel like you have too much air in your lungs because of the negative pressure? I've heard that divers need to let breath out as they rise.

I wonder, can you hold your breath in space? Or does your chest feel like it's getting crushed until you let the breath out? Or would it feel like you have too much air in your lungs because of the negative pressure? I've heard that divers need to let breath out as they rise.

Indeed! As a long-time science fiction reader, I have been puzzled (for an equally long time) about what really happens when a person is exposed to the vacuum of space sans a protective suit. It's a standard plot development that the evil space pirates either threaten to cycle their hapless victims out the air lock, or some horrible misunderstanding leads to a minor character accidentally spacing himself—perhaps as the deserved consequence of failing to heed prominent written instructions. (DO NOT TU

There is a bunch of excellent information out there on the subject. NASA and the DoD have had several incidents happen over the years. The ones providing the most data on survival have been test chambers, where they were testing pressure suits.

Basically, you will most likely pass out in 10 to 30 seconds, from hypoxia. Your blood doesn't boil, due to the pressure contained within your circulatory system.

Really, I don't know. I'd be willing to bet someone over at NASA has pondered it though.

The A/C reply is probably right. I'd think of it like pressurized system. At sea level (14.7psi) a BP of 120/80, that's 2.32psi over 1.55psi.

And this is where I get a headache. Your blood pressure rises as the external pressure drops. Your body responds to the lower amounts of available oxygen. Very likely such an event would increase your blood pressure and pulse rate.

There is no 'boom' created as you cross or exceed the sound barrier. The sonic boom phenomenon is the compressed sound (normally of a jet engine) slamming into you all at once, literally a wall of sound, rather than hearing it as it comes nearer, passes, and moves away from you. A human in free-fall will not to the best of my estimation, create this sonic boom as he is not creating a large amount of sound. Of course if it was me, I would be screaming hysterically all the way down.

Except the shock cone of say, an SR-71 Blackbird, originate at the nose and inlet cones of the aircraft, and these are specifically designed to keep the shockwaves ahead of the engines, and thus keep the airflow in the engines subsonic.
What you are saying is mostly correct, except that this wall of sound is what happens when "sound" starts to behave non-linearly. When you try to push air faster than a certain speed, molecules begin to pile up, density increases, heat increases, and it stops behaving like

Except the shock cone of say, an SR-71 Blackbird, originate at the nose and inlet cones of the aircraft, and these are specifically designed to keep the shockwaves ahead of the engines, and thus keep the airflow in the engines subsonic.

I read that the bow shock on the SR-71 goes into the engines at around mach 3. This provides the engines with pre-compressed air and fuel efficiency actually increases at that point. An old article written by one of the pilots had 2 highlights that I remember - 1) if you're

The sonic boom phenomenon is the compressed sound (normally of a jet engine) slamming into you all at once, literally a wall of sound, rather than hearing it as it comes nearer, passes, and moves away from you.

There will be a sonic boom. The sonic boom is a shock wave created by the displacement of atmosphere caused by the passage of anything traveling faster than the speed of sound. It doesn't matter if the object generates sound in addition to that. For objects falling more or less straight down, the sonic boom propagates towards the horizon and through atmosphere that is far less dense than the lower atmosphere. It's probably possible to detect the sonic boom in question, but it's vastly less energy (and hence

As an aside, the speed of sound depends on temperature and to a modest extent density. At the altitudes he jumped at, the speed of sound is significantly slower than it is at ground level, due to the much colder temperature of the layer he passes through (I'm too lazy to look it up in Wikipedia like I should, but I believe the lowest temperature at that point happens at the tropopause, the boundary between the lower atmosphere and the stratosphere which is somewhere around 70k feet.

There will be a 'boom' of sorts. If you happen to be stationary and near his path of descent, you'll hear it. Baumgartner will not, as he is traveling along with the shock wave. He will experience this wave as constant aerodynamic pressure on his body.

it seems to me that he might experience some problems with part of his body having supersonic shockwaves forming on it before other parts of his body, thanks to the non-aerodynamic shape of his head, shoulders, etc.

similar to airplanes breaking up at the sound barrier before they were designed to fly through it.

Possibly. This might be experienced by unevenly distributed aerodynamic pressure and result in poor attitude control.

The net pressure would be the same (about equal to his body weight) but could be uncomfortable if concentrated at a few limbs or other points.

Airplanes broke up on part due to loss of control due to the ineffectivity of their control surfaces. They'd get into some position where forces exceeded the airframe design strength. That's not likely to happen with a human body in free fall. The max

To be accurate, he will be traveling at terminal velocity all the way down. Its just that terminal velocity is much higher at 100,000 feet than at lower altitudes.

The aerodynamic force a he will experience will be relatively constant, since it will balance that of gravity attempting to accelerate him downwards. As he will be decelerating overall (due to increasing density at lower altitudes), the net aerodynamic pressure will total somewhat more than his body weight.

Due to the substantially lower density of the human body, even a fall from orbit isn't necessarily all that dangerous. One of the issues facing spacecraft designers is that the vehicle is usually made of metal and has an overall density that is quite high (from not just the shell of the spacecraft, but also all of the instruments and supplies as well).

It has been proposed that one possible rescue mode for astronauts in orbit is to perform one of these extreme altitude descents. There still are many things

...but it makes sense when one considers how long it's been since we were really going full-tilt at doing this kind of research in the public sector. (Every time I see it, this xkcd [xkcd.com] leaves me a little more depressed about our willingness, as a population, to go to the risks and expenses necessary to accomplish great things).

Serious kudos to Red Bull for sponsoring this -- it's a happy day when one person's marketing budget is another person's research budget, and I sincerely hope both the PR people and the

It's a good stunt, but science? If anybody really wanted the data they'd just drop the suit without the man in it. If there's still any concern about un-identified paramaters necessary to support life (which I doubt) they could always go the monkey/dog route again. (Granted, Kittinger himself says otherwise in the article, but I still don't see it).

Consider that some of the parameters involve things like human strength and control (for spin avoidance, for instance) -- a weighted suit and a suit being controlled by a human with training don't necessarily behave the same.

The one-man re-entry suit GE built (but never finished testing) back in the day was real research. I don't see why this doesn't qualify similarly.

Moreover -- just dropping the suit without anyone in it could be what they'd do if they only wanted the data. Being a publicity stunt and bei

Orbit is a fair bit higher than this jump. The ISS is 10 times higher than the jump which gives you much more time to build up speed. Whether or not the MOOSE system would really keep the user from burning up on re-entry is still debatable.

Speed is limited by terminal velocity of about 200 km/h near the ground, where it matters.
The total heat generated from air friction during the jump can't be more than the initial potential energy,
but you'd need a profile of the air density to calculate it exactly.

The problem with a spacecraft made of heavy metals is that it drops like a rock through the atmosphere, hence it needs a huge amount of shielding due to the reentry speed when it finally hits the lower atmosphere.

An astronaut with a much more minimal shield doesn't have the same problem due to the lower overall density of the astronaut as composed to a heavy spacecraft, so the altitude where the pressure starts to push back against the astronaut would be much higher, and the astronaut could "skip" across th

I wonder what the heat will be as the atmosphere slows him down from such a drop. I know he's not going at an orbital velocity or anything, but gravity alone will give him quite a lot to slough off. This just looks like a baaaaad idea.

Roughly the same amount of heat accumulated during a skydive from 10,000 ft. You're coming in to contact with the same number of atoms per hour as you do with normal skydiving, which slows your fall the entire way. Your absolute terminal velocity changes along the way, but your relative tV stays the same. It's not like he's jumping out of the ISS, already doing 17,000mph, where he might actually burn up.

There have been several people going supersonic in the atmosphere, after high speed ejections from military aircraft. Supposedly some even jumped out at Mach 3, though as that was during secret tests I'm not sure the details were ever disclosed officially. This would be the first to accelerate to supersonic speed in free fall, not the first to go supersonic.

I remember someone ejecting from a jet at supersonic speed in an outside loop (I think it was in Louisiana) and surviving in pretty good shape. The details escape memory but I think he got out with his legs intact, which had been predicted as improbable, and survived.One of the more memorable ejections in that era was from a Cougar jet disabled in a thunderstorm over Louisiana. He took a very long time to get down and had ribs broken due to the buffeting he received. A REALLY long time to get down due to

The slowest the speed of sound gets is 295.1 m/s or 968 ft./s between 10,000 and 20,000 feet, which translates to 1062 km/h or 660 mph, so no, it seems Kittinger did not reach the speed of sound at any altitude.

What's really cool is the Col. Joe Kittinger (who has the record of 102,000+ feet since I was 2)
is his biggest fan & supporter. Joe did it old school...just throw on a G-suit, space suit, parachute
and jump. When he landed, he popped out a lighter & smoked a cigarette LOL. Times have
changed. That HQ photo of Baumgartner standing on the edge of the capsule is my unlock screen
on my phone. Cool picture. Hope they do one at 120K feet.

I dunno. I did a tandem jump from 12,000 feet and that strong wind on the way down definitely discouraged any thoughts of floating or flying. But the scale is so big that you don't really get the feeling of falling, either.

From TFA: "Thirty seconds after leaping, he’ll exceed the speed of sound in the thin upper atmosphere by traveling almost 700 miles per hour."

The speed of of sound in the upper atmosphere is _not_ 700 miles per hour. That figure relates to the speed of sound at one atmosphere and normal temperatures and also has to consider partial pressures including water vapor. In the upper atmosphere, the speed of sound is much less.

Claims similar to this over the years that the space shuttle is traveling at Mach 25 are just as ill-informed, since the "mach" number is supposed to be based on local conditions, not at some hypothetical place on a beach (one atmosphere, nice temperatures). It is wrong to simply divide some velocity by the speed of sound at sea level and then apply it to conditions present at the object's location.

While your somewhat pedantic point is entirely valid, this is generally done to make the general public understand it in a (dramatic) frame of reference they are familiar with. I do agree it would be better to give the speed in mph (or kmh if you're somewhere with a sane measurement system).

Typical skydives are from 13K. If you go a little more than double like from 30K, you have to wear full O2 mask (not the cheapie like what falls from ceiling on airliners), and have to prebreath 100% O2 on ground before departure (highly recommended to prevent nitrogen bends). Then if you want to double that to 60K, you need a pressure suit. Though Armstrong line is 63K but probably not much difference to your body of 3000 feet.

So 30K which many been on airliner flights (and a few that have jumped from th

I'd like to point out that your blood doesn't boil in a low pressure environment, even if that's a vacuum. As it's contained by your skin and tissues that are rather noncompliant tissue and thus maintain a certain level of internal pressure.

However, the starling forces are severely disrupted, resulting in oedema of any exposed tissue, this however can be compensated for by using skin tight clothing. NASA did in fact once research a wet-suit like space suit that wouldn't be pressure sealed, concept was good, however, if the suit is kinked and the pressure is relieved you get oedema, and this is hard to prevent in regions such as around joints and crotch.

You are likely talking about a documentary regarding Joseph Kittinger [wikipedia.org], the guy who currently holds the high altitude jump record and set that record in 1960. The reason why it hasn't been tried again is in part due to the fact that such jumps have been perceived as being extremely dangerous. Project Excelsior [wikipedia.org], on the third jump by Col. Kittinger, finally did reach an ultimate velocity of 614 mph, or about nine-tenths of the speed of sound. Basically going the speed of many commercial jetliners if you want a comparison.

Part of the current effort for extreme altitude sky dives is in part to suggest an alternative re-entry method for astronauts that might be able to simply parachute to the Earth from LEO using a small thruster pack and perhaps a surfboard sized reentry shield. On top of that, it is one of the few major international aviation records that might be possible for somebody with private funding to break instead of a major military organization.

No, there hasn't been somebody who broke Mach 1 (aka the speed of sound) due to free fall. The extreme altitude being attempted by Baumgartner is going to get to that velocity though, in part because the air is so thin at that altitude that it won't offer much resistance until he gets much lower.

Part of the current effort for extreme altitude sky dives is in part to suggest an alternative re-entry method for astronauts that might be able to simply parachute to the Earth from LEO

Re-entry from orbit is a LOT harder - the lateral speed needed for LEO is ~7 km/s or about 21 times the speed of sound (at sea level). I suppose this is a start but from orbit you'll have ~400 times more KE to dissipate somehow which will not be trivial.